Heated piston



A. D. SKINNER.

HEATED PISTON.

APPLICATION FILED IuIIE 25. 1919.

1,356,943. PaIenIed OCI. 26,1920.

f W C,

' Erie, in the county of kErie and State of v UNITED STATES PATENT OFFICE;l

ALLAN D; SKINNER, or ERIE, PENNSYLVANIA.

HEATED PISTON.

' Application `and :rune 25,

To all whom itmag/ concern.' i

B e it known that I, ALLAN D. SKINNER?, a citizen of the United States, residing at Pennsylvania, have invented certain new yand useful Improvements in Heated Pistons, of which the following is a specification.; l This invention relates to heated pistons especially adapted for uni-directional flow or straight-flow engines, in which the steam enters at one point in the cylinder, preferably at the ends, and is yexhausted through exhaust ports located approximately at the middle portion of the cylinder, which are uncovered by the piston at or near the end of itsworking stroke.

It also applies lto uni-directional flow or straight fiow engines which have, in addition to exhaust ports in the cylinder as above described, auxiliary exhaust ports in the cylinder walls between the exhaust ports land the ends ofthe cylinder.

' It also applies to unaflow engines where the auxiliary exhaust ports are placed at they ends of the cylinder. p

It also applies to counterflow enginesof the usual wellknown types.

Many tests have proved that a saving in the steam economy of unaflow engines is effected by heating the piston above the tem-k perature it would ordinarily have when working in the cylinder.k This heating is most easily effected by allowing part of the steam used in the operation of the engine to gain admittance to the interior of the piss ton and to withdraw the entrained water.

I have found also that the steam trapped inthe cylinder by the advancing piston, after the central exhaust ports have been covered, is very effective for heating the piston, inasmuch as this steam is compressed against the hot walls and heads of the cylinder, which have previouslyA contained steam at boiler pressure-and temperature.r This device allowsthe utilization, for piston heating, of such steam as well as boiler steam which is admitted to the cylinder.

In the drawings, Figure l is a longitudinal section of a unaflow cylinder provided with the invention. Figs. 2 and 3 are details in section. Fig. 4 is a detail of a modification. In the drawings, A is the cylinder; B, the piston C, C the inlet valves; D, thepmiddle Specification of Letters Patent. Patented Oct. 26, 1920.

1,919. Serial N0. 306,614.

exhaust ports; E the exhaust belt; and F, h exhaust pipe connected to the exhaust e t.

At the opposite ends of the cylinder bore, A, areplaced two grooves, G and G one of which, as the piston nears the end of its compression `stroke,.comes into register with a hole, H, drilledin piston, B. Ator'nearthe end of the compression stroke, therefore, some of the compressed steam from the cylinder will` enter the interior of piston,` B, throughthe groove, G, and the hole, H. If the inlet valve is open at this period, some of the boiler steam may also be admitted to the interior'of the piston. y

.As the piston starts on its power stroke toward the left, (in Fig. l) the hole, H, comes out of register with groove, G, and therefore the steamk in thepiston cannot expand into the cylinder.

As the pistonadvances farther, the hole,l

H, at the fright-hand end of the piston, comes in tregister kwith a hole, I, in the cylinends of the cylinder, but' can be placed in otherlocations in the cylinder wall if de-` sired. When the hole, H", in the piston regy isters with thehole, I,*in the cylinder wall,

a certain portion of the steam in the piston,

kwith its entrained water, will be emptied into hole, I, and will operate a draining device, J, more fullyshown in Figs. 2 and 3. y

'This device consists of a tube, K, having a piston,` L, supported by Va spring,"M. lVhen the hole, H', in the piston, comes in register with the hole, I, in the cylinder wall, the entrained water under pressure of the steam inside of the piston is emptied Vinto the hole, I, vand the pressure'ofthis entrained water andv steam forces the small pis-v ton. or' plunger, L, down against lthe stop, N, as shown in Fig. 3. n i If, on account of the rapidity `of the move` ment of the piston, B, the hole, H', is not registered with hole, I, long enough to bring the pressure on top of the small piston, L,`to the same as the pressure inside of the piston, B, another opportunity is given to allow the draining of the piston when the port, H, further on in the stroke, comes in register with the hole, I, in the cylinder wall. f Stop, N, is made adjustable, so that a predetermined amount of entrained water from the piston B can be emptied through hole I, its pressure compressing the spring M, and forcing the piston down against the stop N. The lower the stop N is adjusted, the lower the small piston L will press its spring, M, and the more entrained water and steam will be liberated from interior of the large piston B. Ordinarily practically all the water will be drained out, but to avoid `undesirable loss of steam by possible excessive flow thereof through the piston, the stated adjustment may be made.

` By experiment or calculation, therefore, a proper amount of drainage can be removed from piston.

After the piston has uncovered the port' I toward the end of the stroke toward the left, at which time the central exhaust ports have been opened, pressure is reduced in the cylinder, due to the opening of the exhaust ports; and the spring tension under the small piston, L, forces this piston upwardly and forces with it the entrained water that was deposited from the large piston B. This water, of course, enters the cylinder, but is immediately emptied out through the cylinder exhaust ports D.

A vent hole, O, ispreferably provided in the lower end of thetube, K, to prevent any water which may leak by the small piston from accumulating behind and preventing the telescopic action of the piston.

Fig. 4f shows another means by which part of the steam and entrained water can be removed from the piston. This consists simply of a small groove, P, connectingtwo ofy the central exhaust ports, D-D, thegroove being placed in the cylinder wall that the holes H and H', in the engine piston, B, come in register with same during the pistons movement in the cylinder. 7 hen the holes, H and H', come in register with the groove, I), some of the entrained water is forced by the pressure of the steam inside the piston into the groove and is immediately emptiedinto the central exhaust ports,

This device shown in Fig. 4 does not allow predetermining the amount of entrained water and steam which is to be removed from the interior of engine piston, B, as well as does the device shown in Figs. 1, 2' and 3, for the reason that the groove, vP, will become smaller as the piston wears the cylinder walls, and it may become clogged with foreign matter; but as for draining the piston, it is effective.

I claim: l y Y l. In a steam engine, the combination ofa cylinder, and a hollow piston therein, the cylinder having a middle exhaust port uncovered by the piston at the end of each stroke, and also having a passage in the wall at each end thereof communicating with the compression space at such end, and the piston having a port in the side wall thereof, near each end, either one of which ports registers with one of said passages near the end of the compression stroke, to admit fluid from said compression space into the piston, and the other of which ports communicates with said -exhaust port to exhaust said Vfluid from the piston on the return stroke. i

' 2. In a steam engine, the combination with a cylinderand a hollow piston therein, the cylinder' having a middle exhaust portV uncovered by the piston at the end of each stroke and the piston having a passage at each end communicating with the interior thereof, of means to conduct heating fluid from the compression space of the cylinder through one of said passages into the piston, and means to transfer said Huid from the interior ofthe piston through the other passage to said exhaust port, the last mentioned means including a chamber opening into the cylinder and adapted to register with said passages during the stroke of the piston and to be uncovered by said piston at the end of its strokes, and a spring pressed plunger in said chamber, to eject Huid therefrom.

Y 3. In a steam engine, the combination with a cylinder and a hollow piston therein, the cylinder having an exhaust port uncovered by the piston at the end of its stroke, of means to conduct heating fluid from the compression space in the cylinder into the piston, and means to transfer said fluid from the interior of the piston to the exhaust side of the cylinder, whence it may escape through said port, the last mentioned means including a chamber opening into the cylinder and adapted to register' with said passages during the stroke of the piston, to be uncovered by said piston at the end of its stroke, and means to eject fluidfrom said chamber when it is. so uncovered.

In `testimony whereof, I aflix my signature.

ALLAN D. SKINNER. 

